Schempp was 16 years old and a student at Abington High School in Pennsylvania when, in November 1956, he refused to stand and participate in mandatory Bible-reading at the beginning of the school day, choosing instead to remain seated and read from the Koran.

The school didn't take his insubordination lightly - the principal went so far as to write letters of 'disrecommendation' to the colleges where he applied - but a protracted court battle ended up in the U.S. Supreme Court, where the justices ruled in Abington Township v. Schempp that the Constitution prohibits mandatory recitation of Bible passages or the Lord's prayer in schools.

Now 73, Schempp, an atheist and retired physicist living near Boston, remains a strong advocate of the separation of church and state. He spoke in Rochester Monday night at the invitation of the local chapter of Americans United for Separation of Church and State.

In an interview Monday afternoon, he expressed concern that the principle enshrined in the 1963 Supreme Court case has been coming under attack in recent years, citing as examples the New York town of Greece's pending case in the Supreme Court as well as the challenge to mandated contraceptive coverage in the new health insurance law.

"For many years the country had quieted down after the initial shock of the ruling ... and people agreed (separation of church and state) was a good thing and went on with their lives," he said. "Somehow, with the rise of the religious right and evangelical Christians, the issue has bubbled back to the surface in a real way - a threatening way, in my opinion."

In the Greece case, where two residents challenged the Town Board's practice of opening its meetings with prayers from invited, mostly Christian clergy, he sided with the residents and called the prayers "a slap in the face" to people of other faiths or none at all.

"They insist it's proper for nearly all the prayers to end with 'In the name of Jesus Christ our Savior' or something like that," he said. "That's extremely sectarian and it gives the impression, I think, that the government of Greece endorses that kind of Christianity or religiosity."

Patrick Medeiros, pastor at Greece Assembly of God, disagreed with Schempp on most points, defending the practice in Greece and calling for a more robust place for religion in public life.

"Prayer's been a part of the fabric of our country since its birth," he said. "I don't believe the state should establish a state religion, but as far as saying people of faith can't have any participation in government or the public arena by expressing a prayer - our founding documents don't discourage that."

Robert Goldstein, president of the group that invited Schempp to speak, said his experience as a high school student challenging school policy is an inspiration to activists of all ages and persuasions.

"I think it's important to see these issues can be impacted by ordinary people," Goldstein said. "When there's something going on that's wrong, someone has to have the guts to stand up and say, 'That's not right,' and Ellery did it."